Work machines such as wheel type loaders include work implements capable of being moved through a number of positions during a work cycle. Such implements typically include buckets, forks, and other material handling apparatus. The typical work cycle associated with a bucket includes sequentially positioning the bucket and associated lift arm in a digging position for filling the bucket with material, a carrying position, a raised position, and a dumping position for removing material from the bucket.
Control levers are mounted at the operator's station and are connected to a hydraulic circuit for moving the bucket and/or lift arms. The operator must manually move the control levers to open and close hydraulic valves that direct pressurized fluid to hydraulic cylinders which in turn cause the implement to move. For example, when the lift arms are to be raised, the operator moves the control lever associated with the lift arm hydraulic circuit to a position at which a hydraulic valve causes pressurized fluid to flow to the head end of a lift cylinder, thus causing the lift arms to rise. When the control lever returns to a neutral position, the hydraulic valve closes and pressurized fluid no longer flows to the lift cylinder.
In systems of the above type, the performance or characteristics of the electrohydraulic system changes over time due to wear of the electrohydraulic components. As the characteristics of the electrohydraulic system change, the performance of the electrohydraulic system may fail to correspond to the expectations of the operator. In some instances, the operator may be unable to achieve the performance level desired.
Accordingly, it is an object of this invention to provide an apparatus and method that calibrates an electrohydraulic system such that the performance of the electrohydraulic system is consistent so as to conform to the expectations of the operator.
The present invention is directed to overcoming one or more of the problems as set forth above.